Arc-starting device for vapor discharge devices



Dec. 4, 1934.

K. E. MULLER 1,983,391

ARC STARTING DEVICE FOR VAPOR DISCHARGE DEVICES Filed Oct. 21, 1929 Fig\.

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Inventor: Kurt E. Muller",

ba His Abto-w'neg.

Patented Dec. 4, 1934 UNITED STATES PATENT OFFHIE ARC-STARTING DEVICE FOR VAPOR DISCHARGE DEVICES Kurt E. Miiller, Berlin-Friedenau, Germany, assignor to General Electric Company, a corporation of New York 3 Claims. (Cl. 250-275) My invention relates to starting devices for vapor discharge devices such as mercury arc rectifiers, for example, and especially to starting devices of the type employing a thermostatic 5 member to move an auxiliary electrode into and out of engagement with the cathode.

The above-mentioned starting devices as heretofore utilized avoid the necessity of tilting the rectifier, which is the method often used for small rectifiers, but they have several serious disadvantages. One of these is the fact that the distance through which the arc-starting electrode moves is comparatively small and is incapable of adjustment relative to the level of the mercury cathode which may vary considerably with variations in temperature.

Another disadvantage is that in the devices heretofore available only one operation of the starting electrode was possible with each operation of the thermostatic element. Since rectifiers of this type often require several successive operations of the starting electrode, considerable time may be consumed in the repeated heating and cooling of the thermostatic element.

In accordance with my invention these disadvantages are overcome by an improved thermostatic starting device which is arranged to cause a plurality of successive operations of the starting electrode by means of one operation of the thermostatic element.

The novel features which I believe to be characteristic of my invention are pointed out in the appended claims. My invention itself, however, will best be understood by reference to the accompanying drawing in which Fig. 1 illustrates a sectional view of a mercury arc rectifier provided with a starting device built in accordance with my invention, the device being in such position that the starting electrode is in contact with 40 the cathode. Fig. 2 is a similar view in which the starting electrode is out of contact with the cathode.

Referring to the drawing in detail, illustrates a cross-sectional view of a rectifier provided with a mercury cathode 11 and a starting electrode 12. The starting electrode which may be provided with a weight 13 is supported by a resilient spring member 14 which in turn is fastened to a bimetallic thermostatic member 50 15.

The thermostatic member 15 is mounted upon a base 16 by means of two studs 17 and 18. The base 16 is mounted within the arm 19 of the rectifier 10 and is supported by a lead-in Wire 20 which is connected to member 15 through stud 18. The studs 17 and 18 are spaced from each other so that member 15 is S-shaped When cold and in that position causes the electrode 12 to dip into the mercury of cathode 11. When the member 15 is heated, it assumes the shape of an are as illustrated in Fig. 2 and causes electrode 12 to be lifted out of the mercury of cathode 11. The action of the thermostatic member in changing from the position illustrated in Fig. 1 to that illustrated in Fig. 2 takes place with a snap action causing the electrodes 12 to be lifted from the cathode at a high rate of speed. Due to the spring action of the support 14 and the mass of the electrode, the electrode oscillates back and forth a number of times before coming to rest. This action causes the electrode to strike several arcs thereby making certain the starting of the rectifier.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. An arc-starting device for vapor electric discharge devices including an auxiliary electrode, a thermostatic member operating with a snap action, and means to connect said thermostatic member to said electrode.

2. An arc-starting device for vapor electric discharge devices including an auxiliary electrode, a thermostatic member operating with a snap action, and a flexible member connecting said thermostatic member to said auxiliary electrode.

3. A starting device for mercury arc rectifiers including an auxiliary electrode, a thermostatic member supported at each end and arranged to assume one position when cold and another position when heated, and a spring member connecting said electrode to said thermostatic memher, said thermostatic member changing from said one position to said other position suinciently suddenly when heated to oscillate said electrode through an amplitude sufiicient to operate said electrode-more than once upon a single operation of said thermostatic member.

KURT E. Mt'iLLER. 

